During the takeoff roll of an aircraft, the pilot is required to make several decisions in a very short time period. Perhaps the most important decision, which must be made continuously during takeoff, is whether to continue the takeoff or to abort. This decision depends on several factors which are considered by the pilot in a variety of ways, and great reliance is placed on the experience of the pilot. There are, however, several known systems which propose to assist the pilot by providing a display of information about the aircraft.
Another decision which must be made by the pilot is the amount of thrust (power) to be applied during the takeoff roll. It is not economical merely to apply full thrust, because of the wear on the engines, and the proportion of the thrust which is to be applied is a function of the characteristics of the aircraft and of the runway.
U.S. Pat. No. 4,773,015 (Leland) teaches an aircraft takeoff monitor which measures the actual distance travelled during the takeoff roll and compares this to an expected distance. The expected distance is calculated by an onboard computer based on stored values for the particular aircraft and variables which have been supplied to the computer by the crew. The display comprises two sets of lights which indicate the runway distance which the aircraft has travelled and the distance required to stop. A first of the displays shows the difference between the actual distance travelled and the expected distance. The second of the displays shows the difference between the distance from the end of the runway in which the aircraft can come to a stop and 1000 feet from the end of the runway.
A system recently developed by NASA has been described in the Nov. 3, 1989, issue of Aviation Week & Space Technology. According to this system, a display shows diagrams of the runway and the aircraft on the runway. The position of the diagram of the aircraft represents the actual position of the aircraft on the runway, and other indicia represent the velocity of the aircraft and the expected location of the aircraft when it attains a velocity V.sub.1.